1. Field of the Invention
The present invention is related to a communications system and more particularly to interfacing a communication system with a high speed link.
2. Background of the Invention
State of the art communication systems communicate with other entities, e.g., a public switch telephone network (PSTN) or a business network, over high speed communication links such as what are known as a T1 link for example. A typical T1 link has a data rate on the order of about 1.5 Megabits per second (Mbps). Communications over the high speed link may be shared by several different entities. To share the link, the high speed bandwidth is segmented into several individual channels using any one of a number of available approaches. Each of the entities communicate through a selected one of the channels. So, for example, a 1.544 Mbps T1 line may be segmented into 24 identical channels, each operating at an effective data rate of 64 Kbps. The 24 channels carry message information as well as typical channel control signals (signaling) that indicate channel connection, start of frame, end of frame, etc.
In what is commonly referred to as channel-associated signaling (CAS), each channel contains its own signaling. So, while each of the 24 channels may have an ultimate data transfer rate of 64 kbps, the actual data rate is somewhat reduced because of the included signaling, e.g., 56 kbps.
Another well known signaling method is common channel signaling (CCS) wherein signaling for all of the other channels of the link is carried on one dedicated (common) channel. CCS is well known, especially as applied to integrated services digital network (ISDN) communications. See, for example, Ralph Becker, “ISDN Tutorial” (1996–2000), located at http://www.ralphnb.net/IDSN. So, an example of a typical T1 link configured for CCS one channel is a dedicated signaling channel carrying signals for each of the remaining 23 message channels with all 24 channels at 64 Kbps.
A typical state of the art communication system may connect to both CAS and CCS channels and so, may include both CCS and CAS interfaces. State of the art T1 trunk interface cards may be configured for voice and data applications as either for CAS or CCS as required. Thus, data may be provided to the communications server using Internet Protocol (IP), ISDN, time division multiple access (TDM), global system for mobile (GSM) communications, or the like. To configure and activate the T1 interface for the appropriate protocol, all card parameters must be downloaded from the server. Typically, the protocol for each connection must be established by a customer engineer (CE) configuring the individual system interfaces. The CE must know á priori the correct protocol for each line connected to the interfaces. Only after identifying the correct protocol, can the CE manually configure the interface cards for a proper connection.
Unfortunately, configuration documentation for these interfaces may be questionable or erroneous. Further, if the customer engineer doesn't have á priori knowledge of the protocol used on a particular T1 link, then expensive equipment may be required to identify the type of T1 interface that is already running on adjacent channels. Very often operating this expensive equipment requires special expertise that the customer engineer may or may not have. Either way, end result may be an invalid or incorrect interface configuration exacerbating, installation time and increasing the service effort required for the installation.
Thus, there is a need for simplified interface card configuration method for automatically, identifying CAS or CCS as required for any particular connected communications line and establishing the channel correctly.